1. Field of the Invention
The present invention relates to an apparatus which generates an abridged map produced by simplifying a road map.
2. Description of Related Art
There is a known method for simplifying the shape of a road based upon map data for displaying a map. For example, with the apparatus disclosed in Japanese Patent laid-open application Publication No. 11-202762, the shape of the road is simplified by performing procedures such as straightening or orthogonalization or the like upon the links which specify the road shape in the map data, and by displaying only landmark information within a range which is regulated by a mask. An easily viewed map is provided by displaying a map using the road shape which has been simplified in this manner.
However, with the apparatus disclosed in Japanese Patent laid-open application Publication No. 11-202762, the road shape is simplified by performing procedures such as straightening or orthogonalization or the like upon each of the links. When, among these, an orthogonalization procedure is performed, an influence comes to be exerted upon the positions of the adjacent links, since the positions of the end points of the links undesirably shift. Accordingly it sometimes happens that, when simplifying a road shape which extends over a long distance, the position of the road deviates greatly from its original position.